Organism Deinococcus radiodurans survives extreme asteroid-impact conditions

A Johns Hopkins-led experiment shows the bacterium Deinococcus radiodurans survived simulated Martian impact pressures, with about 60% viability after pressures near 2.4 gigapascals; the study links this resilience to DNA repair systems and a crystalline membrane structure.

Researchers at Johns Hopkins University recreated conditions similar to a Martian asteroid impact to test how much the bacterium Deinococcus radiodurans can withstand. The team, led by mechanical engineers Lily Zhao and K.T. Ramesh, placed bacterial samples between steel plates and applied rapid impacts to generate high dynamic pressures. More than half of the bacteria remained viable after pressures reached roughly 2.4 gigapascals. The results were published in the journal PNAS Nexus and are being discussed for their implications for transfer of life between planetary bodies. Key findings: - The laboratory impact tests exposed D. radiodurans to rapid pressures comparable to asteroid strikes and found survival up to about 2.4 gigapascals, with roughly 60% of cells remaining viable. - The experiment used steel-plate impacts to create dynamic shock; signs of stress and membrane rupture appeared near the 2.4 GPa level. - The bacterium’s resistance is attributed to antioxidant systems and DNA-repair enzymes, and to a crystalline arrangement of proteins in its cell membrane that helps withstand impact stress. - The study notes that pressures up to about 3 gigapascals are relevant to impacts and that earlier work on other microbes often focused on steady hydrostatic pressure rather than rapid shock. - The authors connect the findings to the lithopanspermia hypothesis, saying that transfer of life on ejecta between planets and moons cannot be ruled out and may have been more likely during events such as the Late Heavy Bombardment. Summary: These results bolster the lithopanspermia idea by showing some microbes can survive impact forces that produce ejecta capable of moving between bodies. The authors state that transfer of life to moons with past liquid oceans cannot be ruled out. Undetermined at this time.